Ranorex 7.1 is somewhat old and no longer supported. Please update Ranorex with most recent 7.2.1 (to confirm the problem still exists in this version).

As for uploading screenshots, since you are a new user, with not enough posts, you will have to use a 3rd party file sharing service, like onedrive or dropbox and here place a link to shared file.

BTW, have you tried to to perform checkin using an external TFS program (e.g. TeamExplorer)? I'm not using integrated TFS, due to the speed problems, caused by MSCCI provider, used by Ranorex/TFS integration.